The present invention relates to a buffered peripheral system capable performing a reliable backup operation, and more particularly to a buffered peripheral system, in which important data such as journal can be written in peripheral devices even when a fault is generated in a buffer memory, to allow the system to have a wide range of application.
In a conventional buffered peripheral system, as is evident from, for example, the explanation in the U.S. Pat. No. 4,423,480 with respect to FIG. 2 thereof, after data from a channel has been written in a buffer memory included in a control unit, the control unit writes the data in a plurality of peripheral devices.
In the above peripheral system, however, when an anomaly such as the disconnection of power source is generated in the control unit, there arises a problem that data in the buffer memory is lost or mismatched. In this case, it is required to repeat desired processing from the beginning thereof. Usually, it is possible to obtain journal once more. In a case where the journal cannot be obtained, data indicative of the journal is lost forever. Since the journal is indispensable for the recovery of a fault in a computer system and for a service using the journal, the vanishment of the journal will result in fatal damage.